In general, photometric efficiency of an LED is inversely proportional to the junction temperature of the LED. A major concern of the LED package designer is keeping the die cool to be lower than the junction temperature. In the conventional LED, the chip is mounted at the base of a concave cup (i.e. optical cavity) of one conducting wire and connected to another conducting wire via a connection wire. Accordingly, the packaged die will be damaged easily as a result of thermal stress.
In view of above conventional drawbacks, U.S. Pat. No. 6,274,924 entitled “surface mountable led package” discloses a structure, as shown in FIG. 1. In this structure, a heat sink 10 includes an optional reflective cup 14. The insert-molded leadframe 12 is a filled plastic material molded around a metal frame that provides an electrical path. The light emitting diode die 16 is mounted indirectly via a heat-conducting subbracket 18 to the heat sink 10. Connection wires extend from the LED 16 and the heat-conducting subbracket 18 to metal wires on leadframe 12 that are electrically and thermally isolated from the heat sink 10. An optical lens 20 may be added by mounting a pre-molded thermoplastic lens and an encapsulant or by casting epoxy to cover the LED.
Although the above structure can separate electricity and heat from one another to prevent the die from heat, its composition is very complicated. Accordingly, the present inventor has been made diligent studies with a quiet mind to design and fabricate a solid-state semiconductor light emitting device that provides with simplified composition in which electricity and heat are not separated from one another. The heat-dissipating area is increased by means of a plurality of holders of a leadframe in addition to the use of the heat sink for dissipating heat. Holders are also applied to enhance connection stability between the solid-state semiconductor light emitting device and a circuit board. This solid-state semiconductor light emitting device is provided for the public in accordance with motivations of the present invention.